As demands for greater workpiece utilization continue to rise, one possible area that may be improved is the processing of the outer portion of the workpiece. Often, the outer portion of the workpiece is not implanted or processed to the same extent as the rest of the workpiece. For example, spin coating processes may leave a greater thickness of material near the outer edge due to centripetal force. Implant processes may provide a different dose near the edge of the workpiece since the outer edge may be at a slightly different temperature than the rest of the workpiece. Other non-uniformities also exist in the semiconductor fabrication process. These non-uniformities negatively impact the utilization of the workpiece, as the area near the outer edge of the workpiece may ultimately be wasted.
Efforts have been made to improve the uniformity of these various semiconductor processes. However, there may be limits to the degree of uniformity that may be achieved by these processes.
Therefore, it would be beneficial if there were an apparatus and method for selectively implanting the outer portion of a workpiece. Further, it would be advantageous if this selective implant improved the overall process uniformity of the workpiece without negatively impacting the throughput of the semiconductor fabrication process.